Bun "FileNotFound ... package.json" / ENOENT in CI

Bun could not find package.json (or another file) at the path it expected. In CI this is a working-directory or checkout problem: the job is not running where the project lives.

What this error means

bun install or bun run fails with "error: FileNotFound" or "ENOENT: no such file or directory" referencing package.json or a script path.

Terminal

bun install
error: FileNotFound reading "package.json"
# or:
error: ENOENT: no such file or directory, open 'package.json'

Common causes

The step runs in the wrong directory

The job runs at the repo root or a subfolder that has no package.json, so Bun finds nothing to install or run.

The checkout omitted the project files

A sparse checkout, wrong path filter, or missing checkout step means package.json is not present on the runner.

How to fix it

Set the working directory to the project root

Add a checkout step so files are present on the runner.
Set working-directory to where package.json lives.
Confirm with ls package.json before the Bun step.

.github/workflows/ci.yml

- uses: actions/checkout@v4
- run: bun install
  working-directory: apps/api

Reference files relative to the project

Point script and config paths at files that exist in the checked-out tree so ENOENT does not appear.

How to prevent it

Always run actions/checkout before Bun steps.
Set working-directory to the package root in monorepos.
Avoid sparse checkouts that drop package.json.